Antitwist insert for circular knitting machines and method



T. H. BAIRD Nov. 25, 1969 ANTITWIST INSERT FOR CIRCULAR KNITTING MACHINES AND METHOD Filed Feb. 14, 1968 INVENTOR. v TRUETTE H. BAIRD ATTORNEY United States Patent 3,479,842 ANTITWIST INSERT FOR CIRCULAR KNITTING MACHINES AND METHOD Truette H, Baird, Vaidese, N.C., assignor to Stevens Hosiery Division of J. P. Stevens & Co., Inc., Hickory, N.C., a corporation of Delaware Filed Feb. 14, 1968, Ser. No. 705,460 Int. Cl. D0413 27/34 US. Cl. 66-149 3 Claims ABSTRACT OF THE DISCLOSURE A plurality of non-conductive inserts, each of which has a cylindrical bore located substantially in the center thereof, are placed inside a vacuum draw-down tube which is connected to a circular knitting machine. The inside diameter of the inserts enables a knitted fabric to be pulled away from the flat surface of the draw-down tube and thereby prevents the fabric from clinging to the sides thereof. The resulting loss of friction prevents the fabric from twisting. The proper number and spacing of the inserts may vary with different yarns being used and the length of the knitted fabric.

The present invention relates to circular knitting machines. In one aspect, the invention relates to an improvement in machines for knitting ladies hosiery.

It is common practice in the art of circular knitting ma chines for hosiery and the like to employ a pneumatic take-up wherein a discharge tube, usually of plastic, is positioned to receive the tubular knit stocking as it passes downwardly through the cylinder of the circular knitting machine. A pneumatic take-up of this character serves the dual function of putting the proper tension on the stockin g during the knitting operation and also of carrying away the finished product at the conclusion of the knitting operation.

It has been discovered that, when knitting with nylon and other synthetic yarns, the stocking have a tendency to cling to the stationary discharge tube whereby that portion of the stocking resists rotation. As the upper portion of the stocking is still exposed to rotation by reason of it being carried by the rotatary needle cylinder, the stocking is twisted Within the cylinder thereby exerting improper tension on the stocking and interfering with the proper knitting of the stocking by the needle cylinder and associated mechanism. Furthermore, the clinging of the stocking to the discharge tube also impairs the free travel of the stocking through the tube and sometimes causes temporary jam-up of the stockings in the tube.

Many attempts have been made to eliminate this clinging of the stocking to the tube, for example, by applying an antistatic dressing on the yarn, using high relative humidity, treating the surfaces of the tubing through which the fabric passes to render them antistatic, ionizing the air in the discharge tube adjacent the needle cylinder, and the like. Such procedures have not been entirely satisfactory and normally are only temporary in their action. In addition, many of these procedures are costly and require elaborate changes to be made to the knitting machines.

With the foregoing in mind, it is an object of the present invention to provide a means for eliminating the clinging of the stockings to the discharge tube;

Another object of this invention is to provide an antitwist device which is strong and durable, which is relatively simple in construction, which is easily inserted into the discharge tube of the circular knitting machine, and which is otherwise well adapted for the purposes described;

Other objects and many of the attendant advantages 3,479,842 Patented Nov. 25, 1969 of this invention will be readily appreciated as the same becomes better understood by reference to the following detailed description which is to be considered in connection with the accompanying drawing wherein;

The sole figure in the case is a fragementary sectional view of a circular knitting machine embodying the present invention.

Briefly this invention relates to a circular knitting machine comprising a frame, a hollow needle cylinder mounted on said frame for rotation, means at the top of said cylinder cooperable therewith to form a knitted fabric and pneumatic take-up means including a stationary discharge tube mounted on said frame to extend below said cylinder in registry with the hollow bore thereof and operable to draw air and the knitted fabric tube down wardly through said cylinder and said discharge tube, the improvement therewith comprising a plurality of non-conductive inserts, each of which has a cylindrical bore eX- tending substantially through the center thereof, said inserts being mounted at various intervals along the length of said discharge tube and being adaptable to receive said knitted fabric tube through said bore whereby the knitted fabric tube is pulled away from the flat surfaces of the discharge tube so as to eliminate static charge between said discharge tube and said knitted fabric tube.

Referring now to the drawing, the illustrated embodiment of the knitted machine of the present invention comprises a frame 10 having a hollow needle cylinder 12 mounted therein for rotation by a pair of gears 14 and 16. A fixed base 13 surrounds and supports the upper end of gear 14. A fixed sinker head, shown in section, is surrounded by a sinker cap 19 and is positioned around the upper end of the needle cylinder 12 to support the sinker and other knitting instrumentalities which cooperate with the needle cylinder in conventional manner to form the knitted tubular fabric 20. A dial cap 22 is mounted on a dial support bracket 24.

In the illustrated embodiment of the pneumatic takeup device, a fixed tube 26, shown in half section, is mounted on the frame 10 as indicated at 28 and 29 to project upwardly through the bore of the needle cylinder 12 having its outwardly-flared upward terminal end disposed immediately below the plane of the sinkers in the head 18. A discharge tube 30 is attached at its upper end to the lower terminal end of the cylinder tube 26 to receive the knitted tubular fabric 20 as the knitting thereof is completed. The opposite end of the discharge tube 30 is, in the present instance, connected to a suitable suction device (not shown) to cause the air to float downwardly through the tubes 26 and 30. The invention is equally applicable to other pneumatic take-up devices, for example, such as that shown in US. Patent No. 2,873,596 to Larkin.

In accordance with the invention, a plurality of nonconductive inserts 32, each of which has a cylindrical bore 34 located substantially in the center thereof, are provided at various intervals along the length of tube 30. The inserts are mounted in the tube in any convenient manner such as press fitting, screwing, soldering, or the like. The diameter of the bore 34 is sufficient to permit the passage of the knitted fabric 20* therethrough.

The shape of the insert can be of any design which is compatible with a secure fitting inside of the cylindri cal tube 30. However, it is critical that the bore be of a cylindrical shape in order to prevent twisting of the knitted fabric passing therethrough. The edge of the bore pulls the fabric away from the fiat surface of the tube 30 thereby preventing the fabric from clinging to its sides. This eliminates the friction buildup between the fabric and the sides of the discharge tube and the resulting loss of friction prevents the fabric from twisting.

It is to be understood that the proper number and spacing of inserts may vary with different yarns being used and with different lengths of the knitted fabric. In our preferred embodiment the insert 32 is a ring. The inserts can be composed of any suitable material such as plastics, metals, wood or the like.

Thus, the present invention provides an effective arrangement in circular knitting machines for eliminating difliculties which have arisen in the operation of such machines with pneumatic take-up devices.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that the invention may be practiced otherwise than as specifically described herein.

What is claimed is:

1. A circular knitting machine comprising a frame, a hollow needle cylinder mounted on said frame for rotation, means at the top of said cylinder cooperable therewith to form a tubular knitted fabric and pneumatic take-up means including a stationary discharge tube mounted on said frame to extend below said cylinder in registry with a hollow bore located in said cylinder and operable to draw air and the tubular knitted fabric downwardly through said cylinder and said discharge tube, the combination therewith of a plurality of nonconductive inserts positioned along the inside periphery of said discharge tube at spaced points along the length of said discharge tube, each of said nonconductive inserts having a cylindrical bore located substantially in the center thereof, said cylindrical bore having a diameter of sufficient size to permit the knitted fabric to pass therethrough thereby eliminating the buildup of friction between said tube and said fabric.

2. An apparatus according to claim 1 wherein said inserts are rings.

3. In a process for producing tubular knitted fabric in a knitting machine equipped with a hollow needle cylinder and discharging said tubular knitted fabric through a stationary discharge tube, the improvement of pneumatically conveying said tubular fabric through a stationary discharge tube having a plurality of nonconductive inserts positioned along the inside periphery of said discharge tube at spaced points along the length of said discharge tube, each of said nonconductive inserts having a cylindical bore located substantially in the center thereof, holding said tubular knitted fabric away from the surface of the discharge tube by passing the fabric through the cylindrical bores of said inserts to eliminate the buildup of friction between said discharge tube and said fabric.

References Cited UNITED STATES PATENTS 1,307,358 6/1919 Houseman 5. 66-153 2,844,952 7/1958 Wawzonek.

2,995,913 8/1961 Peel.

3,036,449 5/1962 St. Pierre et al. 66-150 FOREIGN PATENTS 1,440,963 4/1966 France.

1,167,478 4/ 1964 Germany.

MERVIN STEIN, Primary Examiner US. Cl. X.R. 

